docs: def get_gene(self) -> Gene:
          """Get the corresponding gene or raise an exception if it's not the reference node.
  
          :raises: InferCentralDogmaException
          """
          if self.variants:
              raise InferCentralDogmaException('can not get gene for variant')
  
          return Gene(
              namespace=self.namespace,
              name=self.name,
              identifier=self.identifier
          )